As speculation swirled Monday over the shock weekend death of Juice WRLD, local media reported that the rising rapper suffered a seizure as Chicago police and federal agents searched his luggage.

The authorities had been waiting for the artist Sunday on suspicions he was carrying contraband, according to The Chicago Tribune newspaper, which said they discovered drugs, guns and ammunition in the search.

When the artist born Jarad Higgins began "convulsing" the paper said an FBI agent administered two doses of Narcan -- an emergency treatment when opioid overdose is suspected -- which awoke him though he remained incoherent.

The musician was pronounced dead at 3:14 am at a nearby hospital, approximately an hour after the plane landed on Sunday.

Autopsy results remain inconclusive and the Cook County Medical Examiner has ordered additional tests including toxicology and cardiac pathology, it said Monday in a statement.

Local and federal authorities did discover 41 vacuum-sealed bags of marijuana and six bottles of prescription codeine cough syrup along with several guns and ammunition, according to the Tribune, citing law enforcement sources.

Two men identified by police as working security for Higgins were charged with misdemeanors for illegally possessing the guns and ammunition.

No drug charges have been filed. Joseph Fitzpatrick, spokesman for the Northern District of Illinois attorney's office said such charges could be handled out of California, where the rapper's plane originated.

Higgins was scheduled to play at the Rolling Loud Festival this weekend in Los Angeles.

A vigil in his honor is slated for Friday in Chicago's Millennium Park.

The artist was of a generation known as the "SoundCloud rappers" -- a subgenre that takes its name from the streaming platform where its artists first find fame.

The crop of rappers in recent years has become a disruptive movement in hip-hop, combining a lo-fi underground sound with raw, emotional lyrics leading some to dub them "emo rappers."

These musicians whose careers are built on internet stardom often rap about popping pills, notably Xanax, an anti-anxiety medication.